Method of generating plcm for broadcast/multicast service and apparatus thereof

ABSTRACT

A method of generating a public long code mask for a broadcast/multicast service and apparatus thereof are provided, by which, upon performing the broadcast/multicast service, an overhead of a base station or a mobile terminal can be reduced and a delay occurring in the base station or mobile terminal can be reduced. In a method of carrying out a broadcast/multicast service provided via a channel of a mobile communication system, the method includes steps of receiving a flow identifier indicative of the broadcast/multicast service; and generating, based on the received flow identifier, a public long code mask for the channel providing the broadcast/multicast service.

TECHNICAL FIELD

The present invention relates to a method of generating a public longcode mask (PLCM) for use in a mobile communication system, such asCDMA2000, and more particularly, to a PLCM generating method applicableto a broadcast/multicast (BCMC) service provided in such a system.

BACKGROUND ART

A long code is used for channel encryption in a forward channel and todetermine the location of a power control bit. The long code also servesto identify terminals operating in a reverse channel and to reduceinterference with the signals transmitted by other terminals. Thegeneration of a general long code is illustrated in FIG. 1.

Referring to FIG. 1, a long code 13 is generated from a long codegenerator 12 according to a long code mask 11 and generally has a lengthof 42 bits. Then, a mobulo-2 inner product operation 15 is performedusing a transmission signal (X) 14 and the long code (Y) 13.

Methods of performing a broadcast/multicast service in the CDMA2000system require the allocation of a public long code mask using specificidentifiers (ID information) as a reference for PLCM allocation, and theID information may be taken from the respective subscribers or thebroadcast/multicast service itself. It is more efficient to use thebroadcast/multicast service as the reference, whereby one public longcode mask is allocated to each group of subscribers using thebroadcast/multicast service, rather than allocating a public long codemask to each subscriber (user).

It is also efficient to assign one physical channel to each service bytaking the broadcast/multicast service as a reference, so that theassigned physical channel can be shared by various users. The sharedphysical channel for providing a broadcast/multicast service may be aforward fundamental channel (F-FCH) or a forward supplemental channel(F-SCH). Hence, the F-FCH channel is a forward broadcast fundamentalchannel (F-BFCH), and the F-SCH channel is a forward broadcastsupplemental channel (F-BSCH). Regardless of the physical channelshared, however, a user group having the same Walsh code and public longcode mask for a given service shares one channel that is assigned to onebroadcast/multicast service, which defines a specific identifier(BCMC_FLOW_ID) for the provided service, so that one channel and onePLCM are assigned to the identifier. That is, each service has it ownservice identifier, which differs for the Walsh code and PLCM used forthe corresponding channel, and the service identifier is generated by abase station and is transmitted to a mobile station.

Meanwhile, the PLCM used for F-BFCH and F-BSCH channels must be newlygenerated (assigned), to be distinguishable from a PLCM used for eachuser's previous forward or reverse fundamental channel and forward orreverse supplemental channel. The newly assigned PLCM cannot overlap(coincide with) a PLCM currently used by a base station controller.Avoiding this necessitates a transfer of the PLCM from a base station oranchor base station to the base station controller, i.e., a higherlayer, resulting in an undesirable delay and complicating the relatednetwork functions.

DISCLOSURE OF INVENTION

Accordingly, the present invention is directed to a method of generatinga public long code mask for a broadcast/multicast service and apparatusthereof that substantially obviates one or more problems due tolimitations and disadvantages of the related art.

An object of the present invention is to provide a method of generatinga public long code mask for a broadcast/multicast service and apparatusthereof, by which an overhead of a base station or a mobile terminal canbe reduced upon performing the broadcast/multicast service.

Another object of the present invention is to provide a method ofgenerating a public long code mask for a broadcast/multicast service andapparatus thereof, by which a delay occurring in a base station or amobile terminal can be reduced upon performing the broadcast/multicastservice.

Additional advantages, objects, and features of the invention will beset forth in part in the description which follows and in part willbecome apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of theinvention. The objectives and other advantages of the invention may berealized and attained by the structure particularly pointed out in thewritten description and claims hereof as well as the appended drawings.

To achieve these objects and other advantages in accordance with thepurpose of the invention, as embodied and broadly described herein,there is provided a method of carrying out a broadcast/multicast serviceprovided via a channel of a mobile communication system. The methodcomprises steps of receiving a flow identifier indicative of thebroadcast/multicast service; and generating, based on the received flowidentifier, a public long code mask for the channel providing thebroadcast/multicast service.

In another aspect of the present invention, there is provided a methodof providing a broadcast/multicast service provided in a mobilecommunication system. The method comprises steps of assigning a forwardchannel to a broadcast/multicast service; generating a flow identifierof the broadcast/multicast service; and generating, based on thegenerated flow identifier, a public long code mask for the assignedforward channel.

In another aspect of the present invention, there is provided a methodof carrying out a broadcast/multicast service provided via a channel ofa mobile communication system. The method comprises steps of generating,based on a flow identifier indicative of a broadcast/multicast service,a public long code mask for the channel providing thebroadcast/multicast service; multiplexing the generated public long codemask with a transmission signal; and transmitting the multiplexedsignal.

In another aspect of the present invention, there is provided a methodof carrying out a broadcast/multicast service provided via a channel ofa mobile communication system. The method comprises steps of generating,based on a flow identifier indicative of a broadcast/multicast service,a public long code mask for the channel providing thebroadcast/multicast service; multiplexing the generated public long codemask with a received signal; and decoding the multiplexed signal.

In another aspect of the present invention, there is provided a methodof simultaneously receiving a plurality of broadcast/multicast servicesvia a forward channel of a mobile communication system. The methodcomprises steps of receiving a plurality of flow identifiersrespectively indicative of the plurality of broadcast/multicastservices; selecting one of the received flow identifiers; andgenerating, based on the selected flow identifier, a public long codemask for the forward channel.

In another aspect of the present invention, there is provided a methodof receiving a broadcast/multicast service simultaneously via aplurality of forward broadcast supplemental channels of a mobilecommunication system. The method comprises steps of receiving a flowidentifier indicative of the broadcast/multicast service; and generatinga public long code mask, using the received flow identifier and apredetermined portion of a channel identifier for identifying thecorresponding forward broadcast supplemental channel.

In another aspect of the present invention, there is provided, in amobile communication system receiving one broadcast/multicast servicedata flow separated into at least two data flows via at least twoforward broadcast supplemental channels, a public long code maskgenerating method. The method comprises steps of receiving a flowidentifier for identifying the broadcast/multicast service; andgenerating a public long code mask using a first flow identifierallocated to each of the channels and a specific service flow identifierfor identifying a specific broadcast/multicast service data flow withinthe respective forward broadcast supplemental channels.

In another aspect of the present invention, there is provided, in amobile communication system receiving one broadcast/multicast servicedata flow separated into at least two data flows via at least twoforward broadcast supplemental channels, a public long code maskgenerating method. The method comprise steps of receiving a firstbroadcast/multicast service flow identifier allocated to thecorresponding forward broadcast supplemental channel; and generating apublic long code mask using a channel identifier identifying thecorresponding forward broadcast supplemental channel and a firstspecific service flow identifier corresponding to the firstbroadcast/multicast service flow identifier in the corresponding forwardbroadcast supplemental channel, wherein the specific service flowidentifier identifies a specific broadcast/multicast service data flowin each of the corresponding forward broadcast supplemental channels.

In another aspect of the present invention, there is provided, in anetwork multiplexing to transmit data flows of at least twobroadcast/multicast services via one forward channel, a public long codemask generating method. The method comprises steps of generating flowidentifiers for identifying the at least two broadcast/multicastservices, respectively; selecting one of the generated at least two flowidentifiers; and generating a public long code mask using the selectedflow identifier.

In another aspect of the present invention, there is provided, in anetwork transmitting one broadcast/multicast service data flow via atleast two forward broadcast supplemental channels, a public long codemask generating method. The method comprises steps of generating a flowidentifier for identifying a corresponding broadcast/multicast service;and generating a public long code mask using the generated flowidentifier and a predetermined portion of a channel identifier foridentifying the corresponding forward broadcast supplemental channel.

In another aspect of the present invention, there is provided, in anetwork transmitting one broadcast/multicast service data flow via atleast two forward broadcast supplemental channels, a public long codemask generating method. The method comprises steps of generating a flowidentifier for identifying a corresponding broadcast/multicast service;and generating a public long code mask using the generated flowidentifier and a specific service flow identifier for identifying aspecific broadcast/multicast service data flow within the correspondingforward broadcast supplemental channel.

In another aspect of the present invention, there is provided, in anetwork transmitting at least two separated data flows of onebroadcast/multicast service via at least two forward broadcastsupplemental channels, a public long code mask generating method. Themethod comprises steps of generating a flow identifier for identifyingthe broadcast/multicast service; and generating a public long code maskusing a channel identifier for identifying each of the correspondingforward broadcast supplemental channels and a specific service flowidentifier for identifying a specific data flow within each of thecorresponding forward broadcast supplemental channels.

In another aspect of the present invention, there is provided a mobileterminal comprising a first module for receiving and storing a flowidentifier for a broadcast/multicast service; and a second module forgenerating a public long code mask to be used in a channel for thebroadcast/multicast service upon providing the broadcast/multicastservice using the flow identifier for the broadcast/multicast service.In another aspect of the present invention, there is provided a basestation comprising a first module for assigning one forward channel toone broadcast/multicast service, the first module generating a flowidentifier of the broadcast/multicast service; and a second module forgenerating a public long code mask for the assigned forward channelusing the generated flow identifier upon providing thebroadcast/multicast service.

In another aspect of the present invention, there is provided a mobileterminal in a communication system receiving a data flow for each of atleast two multiplexed broadcast/multicast services via one forwardchannel. The mobile terminal comprises a first module for receiving flowidentifiers for respectively identifying the at least twobroadcast/multicast services; a second module for selecting one of thereceived flow identifiers; and a third module for generating a publiclong code mask using the selected flow identifier.

In another aspect of the present invention, there is provided a mobileterminal in a communication system separately receiving at least twodata flows of one broadcast/multicast service via at least two forwardbroadcast supplemental channels. The mobile terminal comprises a firstmodule for receiving a flow identifier for identifying thebroadcast/multicast service; and a second module for generating a publiclong code mask using the received flow identifier and a predeterminedportion of a channel identifier for identifying the correspondingforward broadcast supplemental channel.

In another aspect of the present invention, there is provided a mobileterminal in a communication system separately receiving at least twodata flows of one broadcast/multicast service via at least two forwardbroadcast supplemental channels. The mobile terminal comprises a firstmodule for receiving a flow identifier for identifying thebroadcast/multicast service; and a second module for generating a publiclong code mask using a first flow identifier allocated to each of the atleast two forward broadcast supplemental channels and a specific serviceflow identifier for identifying a specific broadcast/multicast servicedata flow within each of the forward broadcast supplemental channels.

In another aspect of the present invention, there is provided a mobileterminal in a communication system separately receiving at least twodata flows of one broadcast/multicast service via at least two forwardbroadcast supplemental channels. The mobile terminal comprises a firstmodule for receiving a first broadcast/multicast service flow identifierallocated to the corresponding forward broadcast supplemental channel;and a second module for generating a public long code mask using achannel identifier for identifying the corresponding forward broadcastsupplemental channel and a first specific service flow identifiercorresponding to the first broadcast/multicast service flow identifierwithin the corresponding forward broadcast supplemental channel, whereinthe specific service flow identifier identifies a specificbroadcast/multicast service data flow in each of the correspondingforward broadcast supplemental channels.

The above implementations consider a mobile terminal as an example butare equally applicable to a base station in the same manner.

The flow identifier used in generating the public long code mask is forthe first broadcast/multicast service allocated to the correspondingforward channel or the first service identifier corresponding to thefirst broadcast/multicast service flow identifier.

It is to be understood that both the foregoing general description andthe following detailed description of the present invention areexemplary and explanatory and are intended to provide furtherexplanation of the invention as claimed.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings:

FIG. 1 is a block diagram of a general long code generating methodaccording to a background art;

FIG. 2 is a diagram of a PLCM generated for a F-BFCH channel accordingto the present invention;

FIG. 3 is a diagram of a PLCM generated for a F-BSCH channel accordingto the present invention;

FIG. 4 is a diagram of a PLCM generated using one of a plurality ofbroadcast/multicast service flow identifiers assigned to the F-BSCHchannel, as in FIG. 3;

FIG. 5 is a diagram of a PLCM generated a channel identifier, when onebroadcast/multicast service is transmitted via various F-BSCH channels,according to one embodiment of the present invention;

FIGS. 6-8 are diagrams of-a PLCM generated using respective examples ofthe channel identifier of FIG. 5;

FIGS. 9-11 are diagrams of a PLCM generated using examples of the firstbroadcast/multicast service flow identifier, respectively;

FIG. 12 is a diagram of a PLCM generated using a BSR_ID identifier, whenone broadcast/multicast service is transmitted via various F-BSCHchannels, according to another embodiment of the present invention; and

FIG. 13 is a diagram of a PLCM generated using FSCH_ID and BSR_IDidentifiers, when one broadcast/multicast service is transmitted viavarious F-BSCH channels, according to yet another embodiment of thepresent invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts.

In the following detailed description of the present invention, it isassumed that the PLCM has a length of 42 bits. This bit length, however,may be set according to currently applicable standards.

Meanwhile, the first ten bits (upper ten bits) has been allocated forthe header of a 42-bit PLCM, and in generating such a PLCM for F-BFCH orF-BSCH channel use, it should be appreciated that an assignment of aheader value coinciding with (overlapping) any previously used publiclong code mask, or long code mask, is to be avoided. FIGS. 2 and 3 eachshow a PLCM generated according to the present invention, where the PLCMof FIG. 2 is generated for the F-BFCH channel and has a header value of“11100010000” and the PLCM of FIG. 3 is generated for the F-BSCH channeland has a header value is “1100010001.”

Referring to FIGS. 2 and 3, after the upper ten bits are allocated asabove, a broadcast/multicast service flow identifier (BCMC_FLOW_ID) isallocated to the lower 32 bits and may have a set length of 16 bits, 24bits, or 32 bits. In the case of a 16-bit or 24-bit identifier, theremainder of the allocation is padded, i.e., filled with 0s or 1s. Thecontents of the flow identifier is generated for a specificbroadcast/multicast service and is multiplexed with a transmissionsignal. Then, based on a broadcast/multicast service flow identifier asabove, a public long code mask is generated for a forward channelproviding the broadcast/multicast service and is multiplexed with areceived signal, to be decoded on a receiving side. To carry out abroadcast/multicast service provided via a forward channel of a mobilecommunication system, a flow identifier indicative of thebroadcast/multicast service is received, and, based on the received flowidentifier, a public long code mask is generated for the channelproviding the broadcast/multicast service. The received flow identifiercan be stored in a memory of a mobile station or a base station.

In the event of transmitting a plurality of broadcast/multicast serviceflow identifiers, each assigned to one F-BSCH channel, the PLCM can begenerated using any one of the flow identifiers. According to apreferred embodiment of the present invention, a firstbroadcast/multicast service flow identifier (FIRST_FLOW_ID), as shown inFIG. 4, is selected. That is, if the data of two or morebroadcast/multicast services are multiplexed into one F-BSCH channel tobe transmitted, one broadcast/multicast service flow identifier can beselected for use in generating a PLCM for the multiplexed channel, andthe selected flow identifier is preferably the first broadcast/multicastflow identifier allocated to the corresponding F-BSCH channel.

On the other hand, if the data of one broadcast/multicast service isdivided for transmission via more than one F-BSCH channel, PLCMgeneration requires an additional identifier, i.e., a channel identifier(FSCH_ID) as shown in FIG. 5, in which the generated PLCM uses a channelidentifier, in addition to the BCMC_FLOW_ID identifier of FIGS. 2 and 3or the FIRST_FLOW_ID identifier of FIG. 4, according to a firstembodiment of the present invention. That is, the channel identifierindicates a specific F-BSCH channel and is included in the PLCMgenerated when providing one broadcast/multicast service via multipleF-BSCH channels.

The configuration of the PLCM shown in FIG. 5 may be varied according tothe lengths of the FSCH_ID identifier and the header. That is, though anFSCH_ID identifier normally consists of seven bits, as shown in FIG. 6,the PLCM can be variously configured. Particularly, if a seven-bitFSCH_ID identifier is deemed too long to generate the PLCM, a reducednumber of bits may be allocated to the FSCH_ID identifier, to produce anFSCH_ID identifier length of four bits as shown in FIG. 7 or of threebits as shown in FIG. 8. The FSCH_ID identifier may be reduced to alength of five bits, whereupon the header value is “11000” or “00xxx” orto a length of six bits, whereupon the header value is “1100” or “00xx.”

Referring to FIGS. 6-8, illustrating a PLCM generated using an FSCH_IDidentifier according to examples of first embodiment of the presentinvention, a broadcast/multicast service flow identifier (BCMC_FLOW_ID)for generating the PLCM configured as in FIG. 5 enables use of a fulllength channel identifier (FSCH_ID) or reduced length channelidentifiers of four bits or three bits, respectively. In either case,the broadcast/multicast service flow identifier may have a length of 16,24, or 32 bits. If the broadcast/multicast service flow identifier has alength of 16 bits or 24 bits, the public long code mask is padded byfilling the remaining bits with 0s or 1s. In the example of FIG. 6, theentire FSCH_ID identifier is used with a header having a value of “110,”but a header value of “000” or “001” may be used to avoid collision withother channels. In the example of FIG. 7, only the four leastsignificant bits (FSCH_ID_LSB_4) of the channel identifier are used witha header value of “110001,” a header value of “00xxxx” may be used toavoid collision with other channels. In the example of FIG. 8, only thethree least significant bits (FSCH_ID_LSB_3) of the channel identifierare used with a header value of “1100011,” a header value of “1100001”or “1100010” may be used to avoid collision with other channels.

In the examples of FIGS. 6-8, the FIRST_FLOW_ID identifier is the firstBCMC_FLOW_ID identifier allocated to the corresponding F-BSCH channel.In each case, however, the BCMC_FLOW_ID identifier may have a length of16, 24, or 32 bits, as shown in the examples of FIGS. 9, 10, and 11,respectively. When the BCMC_FLOW_ID identifier length is less than 32bits, the unoccupied (unallocated) bits of the 32-bit allocation arefilled with 0s or 1s, i.e., the FIRST_FLOW_ID identifier is padded sothat the entire 32-bit allocation is occupied. Here, the padding isprovided to the upper bits of the 32-bit allocation.

In the examples of FIGS. 9 and 10, BCMC_FLOW_ID identifiers of 16 bitsand 24 bits are used with a seven-bit FSCH_ID identifier and a seven-bitheader, so that the 42-bit PLCM length requires padding lengths oftwelve bits and four bits, respectively. Here, as in the case of theexample of FIG. 8, the header value is “1100011,” but a header value of“1100001” or “1100010” may also be used to avoid collision with otherchannels. The example of FIG. 11, however, requires no padding since theBCMC_FLOW_ID identifier occupies the entire 32-bit allocation, with aseven-bit FSCH_ID identifier and a three-bit header completing the42-bit length of the PLCM. In this example, as in the case of theexample of FIG. 6, the header value is “110,” but a header value of“000” or “001” may also be used to avoid collision with other channels.

FIG. 12 illustrates an example of a PLCM generated using a BSR_IDidentifier, when one broadcast/multicast service is transmitted viavarious F-BSCH channels, according to another embodiment of the presentinvention. Here, the PLCM includes a specific service flow identifier(BSR_ID), which is indicative of a specific BCMC data flow on one of theF-BSCH channels and is preferably a first BSR_ID identifier(FIRST_BSR_ID), and the first broadcast/multicast service flowidentifier (BCMC_FLOW_ID). As in the case of the first embodiment, theBCMC_FLOW_ID identifier may be set as the FIRST_FLOW_ID identifier.

Accordingly, the PLCM configuration of FIG. 12 is a modification of thefirst embodiment of the present invention. That is, the BSR_IDidentifier is used in addition to the BCMC_FLOW_ID identifier of FIGS. 2and 3 or the FIRST_FLOW_ID identifier of FIG. 4, to generate a PLCMaccording to a second embodiment of the present invention. As in thecase of the first embodiment, the broadcast/multicast service flowidentifier may have a length of 16, 24, or 32 bits, and the generatedPLCM is padded if the broadcast/multicast service flow identifier has alength of less than 32 bits. Here, too, as in the case of the examplesof FIGS. 8-10, the header value is “1100011,” but a header value of“1100001” or “1100010” may also be used to avoid collision with otherchannels.

FIG. 13 illustrates an example of a PLCM generated using FSCH_ID andBSR_ID identifiers, when one broadcast/multicast service is transmittedvia various F-BSCH channels, according to yet another embodiment of thepresent invention.

Referring to FIG. 13, the generated PLCM includes a channel identifier(FSCH_ID) indicating a specific F-BSCH channel and a specific serviceflow identifier (BSR_ID) for identifying the data flow of a specificBCMC service being transmitted via the F-BSCH channels. In doing so, theFIRST_BSR_ID identifier, corresponding to the first BCMC_FLOW_IDidentifier allocated to the corresponding F-BSCH channel, can be used asthe BSR_ID identifier. To complete the 42-bit length of the PLCM, aspecific portion or portions can be padded according to a length (n) ofa header; specifically, the upper bits of the FSCH_ID identifier portionare filled with 1s or 1s. In other words, the length of the paddingdepends on the length of the header. For example, if the header lengthis n, the padding length becomes 32−n, so that upper bits, i.e., next tothe header, are filled with 0s or 1s to complete an allocation for theFSCH_ID identifier.

It should be appreciated that each of the embodiments of the presentinvention can be implemented by modules constructing one mobile terminalor one base station.

Accordingly, the present invention generates the PLCM using a knownbroadcast/multicast service identifier, thereby facilitating allocationof a PLCM that avoids overlapping currently used PLCMs (or LCMs) andenabling a reduction in delay time.

INDUSTRIAL APPLICABILITY

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present invention. Thus,it is intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

1. A method of carrying out a broadcast/multicast service provided via achannel of a mobile communication system, the method comprising stepsof: receiving a flow identifier indicative of the broadcast/multicastservice; and generating, based on the received flow identifier, a publiclong code mask for the channel providing the broadcast/multicastservice.
 2. The method as claimed in claim 1, wherein the channel forthe broadcast/multicast service is a shared channel.
 3. The method asclaimed in claim 2, wherein the shared channel is one of a forwardbroadcasting fundamental channel and a forward broadcasting supplementalchannel.
 4. The method as claimed in claim 1, wherein the generatedpublic long code mask includes a specific header for thebroadcast/multicast service.
 5. The method as claimed in claim 4,wherein the specific header has a value that does not coincide withprevious public long code masks and does not coincide with previous longcode masks.
 6. The method as claimed in claim 5, wherein the value ofthe specific header is set to one of “1100010000” and “1100010001.” 7.The method as claimed in claim 6, wherein the value of the specificheader is “1100010000” when the channel is a forward broadcastingfundamental channel
 8. The method as claimed in claim 6, wherein thevalue of the specific header is “1100010001” when the channel is aforward broadcasting supplementary channel
 9. The method as claimed inclaim 4, wherein the generated public long code mask has a length of 42bits.
 10. The method as claimed in claim 9, wherein the specific headerhas a length of ten bits.
 11. The method as claimed in claim 9, whereinthe flow identifier has a length selected from the group consisting of16 bits, 24 bits, and 32 bits.
 12. The method as claimed in claim 11,wherein, if the length of the flow identifier is not 32 bits, the publiclong code mask is padded to fill remaining bits.
 13. The method asclaimed in claim 1, wherein the public long code mask is shared by allmobile terminals provided with the broadcast/multicast service.
 14. Themethod as claimed in claim 1, wherein the generated public long codemask has a length of 42 bits, said generating step comprising a step of:allocating ten upper bits to a specific header, the specific headerhaving a value that does not coincide with previous public long codemasks and does not coincide with previous long code masks, wherein theflow identifier occupies a predetermined length of unallocated bits ofthe generated public long code mask.
 15. The method as claimed in claim14, wherein the value of the specific header is set to one of“1100010000” and “1100010001.”
 16. The method as claimed in claim 15,wherein the value of the specific header is “1100010000” when thechannel is a forward broadcasting fundamental channel
 17. The method asclaimed in claim 15, wherein the value of the specific header is“1100010001” when the channel is a forward broadcasting supplementarychannel
 18. The method as claimed in claim 14, wherein the flowidentifier has a length selected from the group consisting of 16 bits,24 bits, and 32 bits.
 19. The method as claimed in claim 18, wherein, ifthe length of the flow identifier is not 32 bits, the public long codemask is padded to fill a remainder of the 42 bits, the remainderexcluding the specific header allocation and the predetermined lengthoccupied by the flow identifier.
 20. The method as claimed in claim 19,wherein the padded bits are all lower-order bits.
 21. A method ofproviding a broadcast/multicast service provided in a mobilecommunication system, the method comprising steps of: assigning aforward channel to a broadcast/multicast service; generating a flowidentifier of the broadcast/multicast service; and generating, based onthe generated flow identifier, a public long code mask for the assignedforward channel.
 22. The method as claimed in claim 21, furthercomprising a step of providing the generated flow identifier to each ofa plurality of mobile terminals.
 23. The method as claimed in claim 22,wherein said flow identifier providing step is carried out prior to saidforward channel assigning step.
 24. The method as claimed in claim 21,wherein the generated public long code mask is shared by a plurality ofmobile terminals among a service group to be provided with thebroadcast/multicast service.
 25. The method as claimed in claim 21,wherein the forward channel is shared by a plurality of mobile terminalsamong a service group to be provided with the broadcast/multicastservice.
 26. The method as claimed in claim 25, wherein the sharedforward channel is one of a forward broadcasting fundamental channel anda forward broadcasting supplemental channel.
 27. The method as claimedin claim 22, wherein the generated public long code mask has a length of42 bits, said public long code mask generating step comprising a stepof: allocating ten upper bits to a specific header, the specific headerhaving a value that does not coincide with previous public long codemasks and does not coincide with previous long code masks, wherein theflow identifier occupies a predetermined length of unallocated bits ofthe generated public long code mask.
 28. The method as claimed in claim27, wherein the value of the specific header is set to one of“11100010000” and “1100010001.”
 29. The method as claimed in claim 28,wherein the value of the specific header is “1100010000” when thechannel is a forward broadcasting fundamental channel
 30. The method asclaimed in claim 28, wherein the value of the specific header is“1100010001” when the channel is a forward broadcasting supplementarychannel
 31. The method as claimed in claim 27, wherein the flowidentifier has a length selected from the group consisting of 16 bits,24 bits, and 32 bits.
 32. The method as claimed in claim 27, wherein theflow identifier for the broadcast/multicast service occupies aBCMC_FLOW_ID field.
 33. The method as claimed in claim 31, wherein, ifthe length of the flow identifier is not 32 bits, the public long codemask is padded to fill a remainder of the 42 bits, the remainderexcluding the specific header allocation and the predetermined lengthoccupied by the flow identifier.
 34. The method as claimed in claim 33,wherein the padded bits are all lower-order bits.
 35. A method ofcarrying out a broadcast/multicast service provided via a channel of amobile communication system, the method comprising steps of: generating,based on a flow identifier indicative of a broadcast/multicast service,a public long code mask for the channel providing thebroadcast/multicast service; multiplexing the generated public long codemask with a transmission signal; and transmitting the multiplexedsignal.
 36. The method as claimed in claim 35, wherein the flowidentifier is assigned to the broadcast/multicast service prior toproviding the broadcast/multicast service.
 37. A method of carrying outa broadcast/multicast service provided via a channel of a mobilecommunication system, the method comprising steps of: generating, basedon a flow identifier indicative of a broadcast/multicast service, apublic long code mask for the channel providing the broadcast/multicastservice; multiplexing the generated public long code mask with areceived signal; and decoding the multiplexed signal.
 38. The method asclaimed in claim 37, wherein the flow identifier is assigned to thebroadcast/multicast service prior to providing the broadcast/multicastservice.
 39. A method of simultaneously receiving a plurality ofbroadcast/multicast services via a forward channel of a mobilecommunication system, the method comprising steps of: receiving aplurality of flow identifiers respectively indicative of the pluralityof broadcast/multicast services; selecting one of the received flowidentifiers; and generating, based on the selected flow identifier, apublic long code mask for the forward channel.
 40. The method as claimedin claim 39, wherein the forward channel is a forward broadcastsupplemental channel.
 41. The method as claimed in claim 39, wherein theselected flow identifier is a first broadcast/multicast service flowidentifier allocated to the forward channel.
 42. A method of receiving abroadcast/multicast service simultaneously via a plurality of forwardbroadcast supplemental channels of a mobile communication system, themethod comprising steps of: receiving a flow identifier indicative ofthe broadcast/multicast service; and generating a public long code mask,using the received flow identifier and a predetermined portion of achannel identifier for identifying the corresponding forward broadcastsupplemental channel.
 43. The method as claimed in claim 42, wherein thepublic long code mask has a length of 42 bits.
 44. The method as claimedin claim 42, wherein the flow identifier has a length of 32 bits. 45.The method as claimed in claim 42, wherein the channel identifierincludes a maximum of seven bits.
 46. The method as claimed in claim 45,wherein the predetermined portion is the four least significant bits ofthe channel identifier.
 47. The method as claimed in claim 45, whereinthe predetermined portion is the three least significant bits of thechannel identifier.
 48. The method as claimed in claim 42, wherein thepublic long code mask comprises a specific header occupying a mostsignificant bit portion of the public long code mask.
 49. The method asclaimed in claim 48, wherein the channel identifier and the service flowidentifier are arranged from a least significant bit to a moresignificant bit, respectively.
 50. The method as claimed in claim 48,wherein a length of the header is variable according to a length of thechannel identifier.
 51. The method as claimed in claim 50, wherein, ifthe predetermined portion of the channel identifier is less than n bits,where n<7, the header has a length of 10−n bits.
 52. The method asclaimed in claim 42, wherein the header has a length of seven bits,corresponding to one of 1100001, 1100010, and
 1100011. 53. The method asclaimed in claim 42, wherein the header has a length of six bits,corresponding to one of 110001 and 00xxxx.
 54. The method as claimed inclaim 42, wherein, if the channel identifier comprises seven bits, theheader is selected from the group consisting of 110, 000, and
 001. 55.The method as claimed in claim 48, wherein, if the flow identifier has alength less than 32 bits, the flow identifier is padded from a mostsignificant bit adjacent the header.
 56. The method as claimed in claim55, wherein, if the flow identifier and the header have lengths of 16bits and 7 bits, respectively, the flow identifier is padded with twelvebits from the most significant bit adjacent the header.
 57. The methodas claimed in claim 55, wherein, if the flow identifier and the headerhave lengths of 24 bits and 7 bits, respectively, the flow identifier ispadded with four bits from the most significant bit adjacent the header.58. The method as claimed in claim 55, wherein, if the flow identifierand the header have lengths of 32 bits and 3 bits, respectively, theflow identifier is not padded.
 59. In a mobile communication systemreceiving one broadcast/multicast service data flow separated into atleast two data flows via at least two forward broadcast supplementalchannels, a public long code mask generating method comprising steps of:receiving a flow identifier for identifying the broadcast/multicastservice; and generating a public long code mask using a first flowidentifier allocated to each of the channels and a specific service flowidentifier for identifying a specific broadcast/multicast service dataflow within the respective forward broadcast supplemental channels. 60.The method as claimed in claim 59, wherein the public long code mask isgenerated using the first service flow identifier, a first specificservice flow identifier corresponding to the first specific service dataflow, and a specific header.
 61. The method as claimed in claim 60,wherein the public long code mask has a length of 42 bits.
 62. Themethod as claimed in claim 60, wherein the specific header has a valuethat does not coincide with previous public long code masks and does notcoincide with previous long code masks.
 63. The method as claimed inclaim 62, wherein the value of the specific header is selected from thegroup consisting of 1100011, 1100001, and
 1100010. 64. The method asclaimed in claim 59, wherein the first specific service flow identifierhas a length of three bits.
 65. The method as claimed in claim 59,wherein the first specific service flow identifier constructs lower bitsof the public long code mask.
 66. In a mobile communication systemreceiving one broadcast/multicast service data flow separated into atleast two data flows via at least two forward broadcast supplementalchannels, a public long code mask generating method comprising steps of:receiving a first broadcast/multicast service flow identifier allocatedto the corresponding forward broadcast supplemental channel; andgenerating a public long code mask using a channel identifieridentifying the corresponding forward broadcast supplemental channel anda first specific service flow identifier corresponding to the firstbroadcast/multicast service flow identifier in the corresponding forwardbroadcast supplemental channel, wherein the specific service flowidentifier identifies a specific broadcast/multicast service data flowin each of the corresponding forward broadcast supplemental channels.67. The method as claimed in claim 66, wherein the public long code maskis generated using the channel identifier, the first specific serviceflow identifier, and a specific header.
 68. The method as claimed inclaim 67, wherein the public long code mask has a length of 42 bits. 69.The method as claimed in claim 67, wherein the channel identifier andthe first specific service flow identifier have lengths of seven bitsand three bits, respectively.
 70. The method as claimed in claim 69,wherein, if the specific header has a length of n bits, the public longcode mask is padded by as many as 32−n bits.
 71. In a networkmultiplexing to transmit data flows of at least two broadcast/multicastservices via one forward channel, a public long code mask generatingmethod comprising steps of: generating flow identifiers for identifyingthe at least two broadcast/multicast services, respectively; selectingone of the generated at least two flow identifiers; and generating apublic long code mask using the selected flow identifier.
 72. The methodas claimed in claim 71, wherein the selected flow identifier indicates afirst broadcast/multicast service allocated to the corresponding forwardchannel.
 73. In a network transmitting one broadcast/multicast servicedata flow via at least two forward broadcast supplemental channels, apublic long code mask generating method comprising steps of: generatinga flow identifier for identifying a corresponding broadcast/multicastservice; and generating a public long code mask using the generated flowidentifier and a predetermined portion of a channel identifier foridentifying the corresponding forward broadcast supplemental channel.74. The method as claimed in claim 73, wherein the selected flowidentifier indicates a first broadcast/multicast service allocated tothe corresponding forward channel.
 75. In a network transmitting onebroadcast/multicast service data flow via at least two forward broadcastsupplemental channels, a public long code mask generating methodcomprising steps of: generating a flow identifier for identifying acorresponding broadcast/multicast service; and generating a public longcode mask using the generated flow identifier and a specific serviceflow identifier for identifying a specific broadcast/multicast servicedata flow within the corresponding forward broadcast supplementalchannel.
 76. The method as claimed in claim 75, wherein the flowidentifier indicates a first broadcast/multicast service allocated tothe corresponding forward broadcast supplemental channel and wherein thespecific service flow identifier indicates a specific data flow of thefirst broadcast/multicast service.
 77. In a network transmitting atleast two separated data flows of one broadcast/multicast service via atleast two forward broadcast supplemental channels, a public long codemask generating method comprising steps of: generating a flow identifierfor identifying the broadcast/multicast service; and generating a publiclong code mask using a channel identifier for identifying each of thecorresponding forward broadcast supplemental channels and a specificservice flow identifier for identifying a specific data flow within eachof the corresponding forward broadcast supplemental channels.
 78. Themethod as claimed in claim 77, wherein the generated flow identifierindicates a first broadcast/multicast service allocated to thecorresponding forward broadcast supplemental channel.
 79. A mobileterminal comprising: a first module for receiving and storing a flowidentifier for a broadcast/multicast service; and a second module forgenerating a public long code mask to be used in a channel for thebroadcast/multicast service upon providing the broadcast/multicastservice using the flow identifier for the broadcast/multicast service.80. A base station comprising: a first module for assigning one forwardchannel to one broadcast/multicast service, the first module generatinga flow identifier of the broadcast/multicast service; and a secondmodule for generating a public long code mask for the assigned forwardchannel using the generated flow identifier upon providing thebroadcast/multicast service.
 81. In a communication system receiving adata flow for each of at least two multiplexed broadcast/multicastservices via one forward channel, a mobile terminal comprising: a firstmodule for receiving flow identifiers for respectively identifying theat least two broadcast/multicast services; a second module for selectingone of the received flow identifiers; and a third module for generatinga public long code mask using the selected flow identifier.
 82. Themobile terminal as claimed in claim 81, wherein the forward channel is aforward broadcast supplemental channel.
 83. The mobile terminal asclaimed in claim 81, wherein the selected flow identifier is a firstbroadcast/multicast service flow identifier allocated to the forwardbroadcast supplemental channel.
 84. In a communication system separatelyreceiving at least two data flows of one broadcast/multicast service viaat least two forward broadcast supplemental channels, a mobile terminalcomprising: a first module for receiving a flow identifier foridentifying the broadcast/multicast service; and a second module forgenerating a public long code mask using the received flow identifierand a predetermined portion of a channel identifier for identifying thecorresponding forward broadcast supplemental channel.
 85. In acommunication system separately receiving at least two data flows of onebroadcast/multicast service via at least two forward broadcastsupplemental channels, a mobile terminal comprising: a first module forreceiving a flow identifier for identifying the broadcast/multicastservice; and a second module for generating a public long code maskusing a first flow identifier allocated to each of the at least twoforward broadcast supplemental channels and a specific service flowidentifier for identifying a specific broadcast/multicast service dataflow within each of the forward broadcast supplemental channels.
 86. Ina communication system separately receiving at least two data flows ofone broadcast/multicast service via at least two forward broadcastsupplemental channels, a mobile terminal comprising: a first module forreceiving a first broadcast/multicast service flow identifier allocatedto the corresponding forward broadcast supplemental channel; and asecond module for generating a public long code mask using a channelidentifier for identifying the corresponding forward broadcastsupplemental channel and a first specific service flow identifiercorresponding to the first broadcast/multicast service flow identifierwithin the corresponding forward broadcast supplemental channel, whereinthe specific service flow identifier identifies a specificbroadcast/multicast service data flow in each of the correspondingforward broadcast supplemental channels.